Cabinet structure, electronic equipment, and image forming apparatus

ABSTRACT

A cabinet structure includes multiple cover members configured to spatially partition an inside from an outside of a cabinet, and a clearance communicating between the inside and the outside of the cabinet is left between two cover members, the two cover members being adjacent to each other, of the cover members, and a passage defined by the clearance and leading from the inside to the outside of the cabinet through the clearance has a shape with multiple bends.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 14/630,877, filed Feb. 25, 2015, which claims priority to andincorporates by reference the entire contents of Japanese PatentApplication No. 2014-040450 filed in Japan on Mar. 3, 2014.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a cabinet structure includingcover members configured to spatially partition an interior space froman exterior space of a cabinet, and an electronic equipment and an imageforming apparatus each including the cabinet structure.

2. Description of the Related Art

An electro-photographic image forming apparatus generally includes anexterior cover for covering various devices involved in image formingprocesses arranged in a cabinet and for spatially separating inside fromoutside of the cabinet. Examples of such an exterior cover are disclosedin Japanese Laid-open Utility Model Application H7-39097 and JapaneseLaid-open Patent Application No. 2006-293221. Some type of an exteriorcover which forms side surfaces of an image forming apparatus isconfigured to cover a single side surface with multiple exterior-coverpieces in a manner that each exterior-cover piece covers one of regionsinto which the side surface is divided. In one exemplary structureconfiguration of such an exterior cover which covers a single sidesurface with multiple exterior-cover pieces, a region of the apparatuswhere electrical components are contained and a region where a drivedevice is contained are covered with different exterior-cover pieces.The structure configuration in which a single side surface is coveredwith multiple exterior-cover pieces advantageously reduces the size ofexterior-cover piece to be removed by a maintenance person in amaintenance or checkout operation as compared with a structureconfiguration in which the single side surface is covered with a singlelarge exterior cover, thereby facilitating operations.

Meanwhile, an image forming apparatus emits sounds such as operatingsounds of various drive units and rotational sound of a rotating polygonmirror. If transmitted to the outside of the apparatus, such sounds canbe noise uncomfortable to people near the apparatus. Such an exteriorcover as that described above can reduce transmission of these sounds,which can be noise, from the inside to the outside of the apparatus,thereby reducing noise emission.

However, if there is a clearance between adjacent exterior-cover piecesof the multiple exterior-cover pieces, sounds emitted inside theapparatus can leak to the outside through the clearance and can benoise. A technology which can solve this problem is disclosed inJapanese Laid-open Utility Model Application H7-39097. In a structureconfiguration according to this technique, adjacent exterior-coverpieces are partially overlapped in contact with each other so that aclearance through which sounds can leak is not left.

However, the various drive units of the image forming apparatus not onlyemit sounds but also generate heat in their operation. The structureconfiguration described above in which adjacent exterior-cover piecesare partially overlapped in contact with each other is disadvantageousin that not only sounds but also air flow are reduced by the eliminationof the clearance, which leads to an undesirable temperature rise insidethe cabinet.

This problem is not limited to image forming apparatuses but can arisein any cabinet structure including multiple cover members whichspatially partition inside from outside of the cabinet.

Under the circumstances, there is a need for a cabinet structureincluding multiple cover members and capable of reducing sound leakagewhile reducing a temperature rise inside the cabinet, and an electronicequipment and an image forming apparatus each including the cabinetstructure.

It is an object of the present invention to at least partially solve theproblems in the conventional technology.

SUMMARY OF THE INVENTION

It is an object of the present invention to at least partially solve theproblems in the conventional technology.

There is provided a cabinet structure that includes multiple covermembers configured to spatially partition an inside from an outside of acabinet, and a clearance communicating between the inside and theoutside of the cabinet is left between two cover members, the two covermembers being adjacent to each other, of the cover members, and apassage defined by the clearance and leading from the inside to theoutside of the cabinet through the clearance has a shape with multiplebends.

The above and other objects, features, advantages and technical andindustrial significance of this invention will be better understood byreading the following detailed description of presently preferredembodiments of the invention, when considered in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an enlarged horizontal cross-sectional view of a boundarybetween a second left-side cover and a third left-side cover of aprinter according to an embodiment of the present invention;

FIG. 2 is a schematic configuration diagram of a printer according to anembodiment of the present invention;

FIG. 3 is a schematic configuration diagram of a process unit of theprinter;

FIG. 4 is a perspective explanatory view of the printer including aleft-side cover made up of multiple exterior-cover pieces;

FIGS. 5A and 5B are explanatory diagrams of a structure configuration inwhich the third left-side cover is configured as a hinged cover memberoperable to open and close, with FIG. 5A being an explanatory diagram ofa state where the third left-side cover is being closed, FIG. 5B beingan explanatory diagram of a state immediately after the third left-sidecover is closed with a force greater than necessary;

FIG. 6 is a perspective explanatory view of the printer, illustrating anexample of a structure configuration in which each of a front cover anda right-side cover individually includes a hinged cover member;

FIG. 7 is an enlarged horizontal cross-sectional view of a boundarybetween a hinged front cover and a hinged right-side cover of theprinter;

FIG. 8 is an enlarged horizontal cross-sectional view of the boundarybetween the second left-side cover and the third left-side cover eachhaving tapered shapes;

FIGS. 9A and 9B are explanatory diagrams of a structure configuration inwhich a rib is arranged on a portion of a projecting cover section, withFIG. 9A being an enlarged horizontal cross-sectional view of theboundary between the second left-side cover and the third left-sidecover, FIG. 9B being an explanatory diagram of the third left-side coveras viewed from the right side of FIG. 9A;

FIGS. 10A and 10B are top views of a structure configuration with threebends, schematically illustrating the projecting cover section and aprojecting-cover-section accommodating section that are deformed, withFIG. 10A being an explanatory diagram of pre-deformation, FIG. 10B beingan explanatory diagram of post-deformation; and

FIGS. 11A and 11B are top views of a structure configuration with twobends, schematically illustrating the projecting cover section and theprojecting-cover-section accommodating section that are deformed, withFIG. 11A being an explanatory diagram of pre-deformation, FIG. 11B beingan explanatory diagram of post-deformation.

FIG. 12 is a diagram illustrating cross sections of the cover membersand a positioning member (structure body).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Exemplary embodiments of the present invention are described below. Inan embodiment, an image forming apparatus according to an aspect of thepresent invention is implemented as an electro-photographic printer(hereinafter, simply referred to as the “printer 100”).

A basic configuration of the printer 100 according to the embodiment isdescribed below.

Referring to FIG. 2 which is a schematic configuration diagramillustrating the printer 100, the printer 100 includes four processunits 26 (K, C, M, and Y) for forming a black (K)-toner image, a cyan(C)-toner image, a magenta (M)-toner image, and a yellow (Y)-tonerimage, respectively. The process units 26 (K, C, M, and Y) are identicalin configuration except in using K toner, C toner, M toner, and Y tonerof different color as an image-forming substance. Each of the processunits 26 (K, C, M, and Y) can be replaced when reaching end of itsusable life.

FIG. 3 is an enlarged explanatory diagram of one of the four processunits 26. The four process units 26 are similar to each other except forthe color of the toner to be used. Accordingly, the letters (K, C, M,and Y), each added to the end of reference numerals of elements toindicate a corresponding toner color, are omitted from FIG. 3.

As illustrated in FIG. 3, the process unit 26 includes a photoconductorunit 10 and a developing unit 23. The photoconductor unit 10 includes adrum-like photoconductor 24, which is a latent-image bearer, aphotoconductor cleaning device 83, a neutralization device (not shown),and a charging device 25. The process unit 26, which is an image formingunit, is detachably attached to a body of the printer 100 so thatconsumables can be replaced at one time.

The charging device 25 uniformly charges a surface of the photoconductor24 that is rotated clockwise in FIG. 3 by a drive unit (not shown). Theuniformly-charged surface of the photoconductor 24 is exposed to laserlight L scanning the surface. As a result, an electrostatic latent imagefor a corresponding one of the colors is formed on the surface. Thedeveloping unit 23 develops the electrostatic latent image into a tonerimage using toner (not shown). The toner image is transferred onto anintermediate transfer belt 22, which will be described later.Hereinafter, this transfer process may be referred to as “primarytransfer”.

The photoconductor cleaning device 83 removes transfer-residual toneradhering to the surface of the photoconductor 24 after the primarytransfer. The neutralization device neutralizes residual chargesremaining on the photoconductor 24 after the cleaning. By thisneutralization, the surface of the photoconductor 24 is initialized tobe ready for a next image forming cycle.

A cylindrical drum portion of the photoconductor 24 is produced bycovering an outer surface of a hollow aluminum pipe with an organicphotoconductive layer. The photoconductor 24 is obtained by attachingflanges each having a drum shaft to both axial ends of the drum portion.

The developing unit 23 includes a vertically-elongated hopper portion86, which contains toner (not shown) as a developer, and a developingportion 87. An agitator 88 and a toner supply roller 80 are arranged inthe hopper portion 86 which is a developer container. The agitator 88 isdriven to rotate by a drive unit (not shown). The toner supply roller 80which is a developer supply member is arranged vertically below theagitator 88 and driven to rotate by a drive unit (not shown). The tonerin the hopper portion 86 moves toward the toner supply roller 80 underits own weight while being agitated by the agitator 88 that is driven torotate. The toner supply roller 80 includes a metal cored bar and aroller portion made of foamed plastic or the like covering the surfaceof the cored bar. The toner supply roller 80 rotates while causing toneraccumulated in an internal lower portion in the hopper portion 86 toadhere to the surface of the toner supply roller 80.

A developing roller 81 and a doctor blade 82 are arranged in thedeveloping portion 87 of the developing unit 23. The developing roller81 rotates in contact with the photoconductor 24 and the toner supplyroller 80. The doctor blade 82 brings its distal end into contact with asurface of the developing roller 81. The toner adhering to the tonersupply roller 80 in the hopper portion 86 is supplied to the surface ofthe developing roller 81 at an abutment part where the developing roller81 contacts the toner supply roller 80. The thickness of layer of thetoner on the surface of the developing roller 81 is adjusted when causedto pass through the abutment position between the doctor blade 82 andthe developing roller 81 by rotation of the developing roller 81. Afterundergoing the layer thickness adjustment, the toner adheres to theelectrostatic latent image on the surface of the photoconductor 24 at adeveloping area, which is an abutment part between the developing roller81 and the photoconductor 24. Development of the electrostatic latentimage into a toner image is thus performed with the toner adhering tothe image.

Such toner image formation as described above is performed by each ofthe process units 26. Consequently, toner images of the respectivecolors are formed on the respective photoconductors 24 of the processunits 26.

As illustrated in FIG. 2, an optical writing unit 27 is arrangedvertically above the four process units 26. The optical writing unit 27,which is a latent-image writing device, optically scans thephotoconductors 24 of the four process units 26 with the laser light Lemitted from a laser diode (not shown) in accordance with image data. Bythis optical scanning, electrostatic latent images of the respectivecolors are formed on the photoconductors 24. In the configurationdescribed above, the optical writing unit 27 and the four process units26 function as an image formation unit which forms K, C, M, and Y tonerimages, or visible images of different colors, on three or morelatent-image bearers.

The optical writing unit 27 irradiates the photoconductor with the laserlight L emitted from the light source via multiple optical lenses andmirrors while deflecting the laser light L in the main-scanningdirection using a polygon mirror (not shown) driven to rotate by apolygon motor. An optical writing unit configured to perform opticalwriting with LED (light-emitting diode) light emitted from multiple LEDsof an LED array may alternatively be employed.

A transfer unit 75 is arranged vertically below the four process units26. The transfer unit 75 is a belt device that causes the endlessintermediate transfer belt 22 to revolve counterclockwise in FIG. 2while supporting the intermediate transfer belt 22 in a stretched closedloop. The transfer unit 75 includes, in addition to the intermediatetransfer belt 22, a driving roller 76, a tension roller 20, four primarytransfer rollers 74 (K, C, M, and Y), a secondary transfer roller 21, abelt cleaning device 71, and a cleaning backup roller 72.

The intermediate transfer belt 22 which is a belt member serving as atransfer belt is supported in the stretched closed loop by the drivingroller 76, the tension roller 20, the cleaning backup roller 72, and thefour primary transfer rollers 74 (K, C, M, and Y) arranged inside theloop. The intermediate transfer belt 22 is revolved counterclockwise inFIG. 2 by a rotational force exerted by the driving roller 76 that isdriven to rotate by a drive unit (not shown) in the same direction.

The four primary transfer rollers 74 (K, C, M, and Y) and thephotoconductors 24 (K, C, M, and Y) pinch the intermediate transfer belt22 revolved in this manner therebetween. By this pinching, a primarytransfer nip is formed at each of four points where the front surface ofthe intermediate transfer belt 22 is in contact with the photoconductors24 (K, C, M, and Y).

A primary transfer bias is applied from a transfer power source (notshown) to each of the primary transfer rollers 74 (K, C, M, and Y). Theprimary transfer bias induces a transfer electric field between each ofthe electrostatic latent images on the photoconductors 24 (K, C, M, andY) and the primary transfer rollers 74 (K, C, M, and Y). A transfercharger, a transfer brush, or the like may be employed in lieu of theprimary transfer rollers 74.

The Y toner image formed on the surface of the photoconductor 24Y of theprocess unit 26Y for yellow is advanced to enter the primary transfernip for yellow by rotation of the photoconductor 24Y for yellow. At theprimary transfer nip for yellow, the Y toner image isprimary-transferred from the photoconductor 24Y for yellow onto theintermediate transfer belt 22 by an action of the transfer electricfield and a nip pressure. By the revolving motion of the intermediatetransfer belt 22, the Y toner image primary-transferred onto theintermediate transfer belt 22 is caused to pass through the primarytransfer nips for M, C, and K, at which the M, C, and K toner images onthe photoconductors 24 (M, C, and K) are sequentiallyprimary-transferred onto the Y toner image to be overlaid on oneanother. By this primary transfer which overlays the toner images on oneanother, four color-toner images are formed on the intermediate transferbelt 22.

The secondary transfer roller 21 of the transfer unit 75 is arrangedoutside the loop of the intermediate transfer belt 22 in a manner topinch the intermediate transfer belt 22 between the secondary transferroller 21 and the tension roller 20 arranged inside the loop. By thispinching, a secondary transfer nip where the front surface of theintermediate transfer belt 22 contacts the secondary transfer roller 21is formed. A secondary transfer bias is applied from a transfer powersource (not shown) to the secondary transfer roller 21. The secondarytransfer bias applied in this manner induces a secondary-transferelectric field between the secondary transfer roller 21 and the tensionroller 20 which is grounded.

A paper feeding cassette 41 which contains a paper bundle formed bystacking multiple sheets of recording paper is arranged vertically belowthe transfer unit 75. The paper feeding cassette 41 is attachable anddetachable to and from a cabinet of the printer 100 by sliding the paperfeeding cassette 41. The paper feeding cassette 41 places a paperfeeding roller 42 in contact with an uppermost sheet of the recordingpaper of the paper bundle and delivers the sheet of the recording paper(hereinafter, the “recording sheet”) toward a paper feeding path byrotating the paper feeding roller 42 counterclockwise in FIG. 2 at apredetermined timing point.

A pair of registration rollers 43 including two registration rollers isarranged near a downstream end of the paper feeding path. The pair ofregistration rollers 43 stops rotations of the rollers immediately uponreceiving and pinching therebetween the recording sheet, which is arecording member, delivered from the paper feeding cassette 41. The pairof registration rollers 43 starts rotating again to deliver therecording sheet pinched therebetween to the secondary transfer nip at atiming point which allows synchronizing the recording sheet with thefour color-toner images on the intermediate transfer belt 22 in thesecondary transfer nip.

The four color-toner images on the intermediate transfer belt 22 arebrought into close contact with the recording sheet in the secondarytransfer nip and jointly secondary-transferred onto the recording sheetby the action of the secondary-transfer electric field and a nippressure, thereby forming a full-color toner image against a whitebackground of the recording sheet. Hereinafter, this transfer step maybe referred to as “secondary transfer”. When the recording sheet onwhich the full-color toner image is thus formed goes out of thesecondary transfer nip, the recording sheet is separated from thesecondary transfer roller 21 and the intermediate transfer belt 22 bycurvature separation. Thereafter, the recording sheet is delivered intoa fixing device 40, which is a fixing unit, via a post-transferconveyance path.

Transfer-residual toner which has not been transferred to the recordingsheet may remain on the intermediate transfer belt 22 exited from thesecondary transfer nip. The transfer-residual toner is removed from thebelt surface by the belt cleaning device 71 that is in contact with thefront surface of the intermediate transfer belt 22. The cleaning backuproller 72 arranged inside the loop of the intermediate transfer belt 22supports the belt cleaning performed by the belt cleaning device 71 frominside the loop.

The fixing device 40 includes a fixing roller 45 which internallyincludes a heat source 45 a such as a halogen lamp, and a pressureroller 47 which rotates while maintaining contact with the fixing roller45 with a predetermined pressure. The fixing roller 45 and the pressureroller 47 form a fixing nip therebetween. The recording sheet deliveredinto the fixing device 40 is pinched in the fixing nip in a manner thatbrings a surface of the recording sheet, on which the not-fixed-yettoner image is carried, into close contact with the fixing roller 45.Heat and pressure applied at the fixing nip softens toner in the tonerimage to thereby fix the full-color image.

If one-sided printing mode has been set by manipulating an operatingunit (not shown) which includes a numeric keypad and the like or inaccordance with a control signal fed from a personal computer (notshown) or the like, the recording sheet discharged out of the fixingdevice 40 is directly discharged to the outside of the apparatus.Thereafter, the recording sheet is stacked in a stacker which is a topsurface of an upper cover 56 of the cabinet.

In the embodiment, the four process units 26 (K, C, M, and Y) and theoptical writing unit 27 make up a toner-image forming unit which formstoner images.

The upper cover 56 of the cabinet of the printer 100 is supported to bepivotable on a shaft member 51 as indicated by arrow A in FIG. 2. Bybeing rotated counterclockwise in FIG. 2, the upper cover 56 is placedin an open state with respect to the cabinet of the printer 100. In theopen state, the upper cover 56 widely exposes a top opening of thecabinet of the printer 100. The optical writing unit 27 is alsosupported to be pivotable on the shaft member 51. Rotating the opticalwriting unit 27 counterclockwise in FIG. 2 exposes top surfaces of thefour process units 26 (K, C, M, and Y).

Attaching/detaching of the process unit 26 (K, C, M, Y) is performedwith the upper cover 56 and the optical writing unit 27 open. Morespecifically, the process unit 26 (K, C, M, Y) is detached from the bodyof the printer 100 by exposing the top surface of the process unit 26(K, C, M, Y) by opening the upper cover 56 and the optical writing unit27 and thereafter pulling out the process unit 26 (K, C, M, Y)vertically upward.

Attaching/detaching of the process unit 26, which is frequentlyperformed, with the upper cover 56 and the optical writing unit 27 open,allows a user or a maintenance person to check the attaching/detachingoperation while viewing inside the cabinet from above without taking astressful posture such as a squatting position, a bending-down positionor a bowed position. Accordingly, reducing work load and reducingerroneous operations can be achieved.

In the embodiment, the process units 26 each including thephotoconductor unit 10 and the developing unit 23 are configured to beattachable and detachable to and from the printer 100. Alternatively,the photoconductor unit 10 and the developing unit 23 may be configuredto be separately attachable and detachable to and from the printer 100.

FIG. 4 is a perspective explanatory view of the printer 100,illustrating an exemplary structure configuration in which a left-sidecover 110 covering a left-side (in FIG. 2) surface of the printer 100 isformed from multiple exterior-cover pieces.

As illustrated in FIG. 4, the left-side cover 110 is formed from fourexterior-cover pieces that are a first left-side cover 111, a secondleft-side cover 112, a third left-side cover 113, and a fourth left-sidecover 114.

The printer 100 includes a body frame 150 (see FIG. 1) which supportsvarious devices for use in image forming. The left-side cover 110 isfixed to the body frame 150 with screws in a state that enables toremove the multiple exterior-cover pieces at maintenance, componentreplacement, or the like occasion. The body frame may be typically madeof a metal such as iron or aluminum. However, the material of the bodyframe is not limited to a metal and can be any material havingsufficient rigidity to support the devices.

Features of the printer 100 are described below.

FIG. 1 is an enlarged horizontal cross-sectional top view of a boundarybetween the second left-side cover 112 and the third left-side cover 113of the printer 100. Reference numeral “150” in FIG. 1 denotes the bodyframe. The second left-side cover 112 and the third left-side cover 113are mounted on the body frame 150 by being pushed thereagainst from theleft side in FIG. 1. When mounted, positions of the second left-sidecover 112 and the third left-side cover 113 relative to the body of theprinter 100 are fixed. When fixed to the body of the printer 100, theexterior-cover pieces including the second left-side cover 112 and thethird left-side cover 113 spatially partition the inside from theoutside of the printer 100. In FIG. 1, the inside of the printer 100 ison the right side with respect to the second left-side cover 112 and thethird left-side cover 113, while the outside of the printer 100 is onthe left side.

The body frame 150 fixes, as a positioning member, the positions of thesecond left-side cover 112 and the third left-side cover 113. The bodyframe 150 is configured so that, even if the second left-side cover 112and the third left-side cover 113 are attached to the printer 100, thesecond left-side cover 112 and the third left-side cover 113 do notcontact each other but leave a clearance 200 therebetween.

Because the clearance 200 allows air to pass therethrough, heatgenerated inside the printer 100 can be discharged to the outsidethrough the clearance 200, and a temperature rise inside the printer 100can be reduced.

The third left-side cover 113 includes, at one end of the thirdleft-side cover 113 on the side of the second left-side cover 112, aprojecting cover section 113 a which is inwardly projecting. The secondleft-side cover 112 includes, at one end of the second left-side cover112 on the side of the third left-side cover 113, aprojecting-cover-section accommodating section 112 a which is configuredso as to surround three sides of the projecting cover section 113 a. Theprojecting cover section 113 a faces the projecting-cover-sectionaccommodating section 112 a without contact between a surface of theprojecting cover section 113 a and a surface of theprojecting-cover-section accommodating section 112 a, thereby creatingthe clearance 200.

A passage defined by the clearance 200 and leading from the inside tothe outside of the printer 100 through the clearance 200 has a shapewith multiple bends.

The printer 100 emits various sounds including operating sounds of drivemotors from which rotations are transmitted to various rollers, soundscaused by movements of moving members such as the various rollers, androtational sound of the polygon mirror of the optical writing unit 27.If transmitted to the outside of the printer 100, such sound can be anoise uncomfortable to people near the printer 100. The exterior-coverpieces which spatially partition the inside from the outside of theprinter 100 can reduce transmission of the sounds emitted inside of theprinter 100 to the outside, thereby suppressing noise emission.

As illustrated in FIG. 1, the clearance 200 is left between the secondleft-side cover 112 and the third left-side cover 113. The clearance 200assumes the labyrinthine shape having the multiple bends. Accordingly,sound waves emitted inside the printer 100 and traveling toward theoutside through the clearance 200 are not allowed to go out of theprinter 100 unless the sound waves are diffracted multiple times.

Thus, sound leakage can be suppressed while preventing a temperaturerise inside the printer 100 by providing the clearance 200 between theexterior-cover pieces or, in other words, by allowing air to flowbetween the inside and the outside of the printer 100.

More specifically, a portion of sound waves traveling as indicated byarrow “a” in FIG. 1 is diffracted at a first diffraction opening 200 aand travels as indicated by arrow “b”. The first diffraction opening 200a is a portion of the clearance 200 between a distal-end surface of theprojecting-cover-section accommodating section 112 a and an inner wallof the third left-side cover 113.

The portion of the sound waves traveling as indicated by the arrow “b”is diffracted at a second diffraction opening 200 b and travels asindicated by arrow “c”. The second diffraction opening 200 b is aportion of the clearance 200 between a surface, which is next to thedistal-end surface, of the projecting-cover-section accommodatingsection 112 a and a distal end portion of the projecting cover section113 a.

Furthermore, the portion of the sound waves traveling as indicated bythe arrow “c” is diffracted at a third diffraction opening 200 c andtravels as indicated by arrow “d”. The third diffraction opening 200 cis a portion of the clearance 200 between a distal-end surface of theprojecting cover section 113 a and a surface, which faces the distal-endsurface of the projecting cover section 113 a, of theprojecting-cover-section accommodating section 112 a.

By employing this structure configuration that does not allow soundwaves emitted inside the printer 100 to leak out from the printer 100unless the sound waves are diffracted multiple times in this manner, atemperature rise inside the printer 100 can be reduced while obtaining asound-shielding effect without utilizing an additional member.

The printer 100 is an electronic equipment that includes drive devicesand the optical writing unit 27, each of which can be a sound sourcethat emits sound when in operation, and further includes theexterior-cover pieces which form the cabinet that covers these deviceswhich can be sound sources. Providing the labyrinthine clearance 200 ata boundary between adjacent ones of the exterior-cover pieces of theprinter 100 enables to reject heat generated by operation of the printer100 through the clearance 200, thereby reducing a temperature riseinside the cabinet of the printer 100. Furthermore, the labyrinthineshape of the clearance 200 enables to reduce leakage of operating soundsof the printer 100 to the outside.

As illustrated in FIG. 1, the clearance 200 has three bends.Accordingly, the clearance 200 is capable of diffracting sound wavestraveling to the outside therethrough a larger number of times than aclearance having two bends, and therefore can enhance the sound-leakageprevention effect.

In the structure configuration illustrated in FIG. 1, the labyrinthineclearance 200 is created between the two exterior-cover pieces.Alternatively, a structure configuration in which a portion of the bodyframe 150 creates a portion of the clearance 200 may be employed. Inthis alternative structure configuration, the portion of the body frame150 functions as a cover member.

The cover members that form therebetween the clearance according to anaspect of the invention may alternatively be interior-cover pieces(which may referred to as “inner-cover pieces”) arranged inside theexterior-cover pieces so as to be exposed when at least one of theexterior-cover pieces is removed or when one or more exterior-coverpieces, which are operable to open and close, of the exterior-coverpieces is opened.

The cover members that leave therebetween the clearance according to anaspect of the invention are not limited to the exterior-cover pieces orthe interior-cover pieces of the image forming apparatus. Alternatively,the cover members may be cover members of a cabinet structure of adevice, such as the optical writing unit 27 or one or more of the drivedevices, arranged inside the image forming apparatus.

Japanese Laid-open Patent Application No. 2006-293221 discloses astructure configuration in which a clearance having only a single bendis left at a boundary between two exterior-cover pieces. However, if theclearance has only the single bend, sound waves obliquely entering thebend can travel straight without undergoing diffraction at the bend andeventually leak to the outside of the image forming apparatus. Bycontrast, the clearance 200 according to the embodiment has the multiplebends and, accordingly, can reduce leakage of sound waves travelingstraight and reduce sound leakage.

The clearance 200 is sized to permit fluctuations in tolerances ofcomponents including the second left-side cover 112 and the thirdleft-side cover 113. More specifically, dimensions of the clearance 200are set to such values that will not cause the clearance 200 to beclosed by the second left-side cover 112 and the third left-side cover113 even in a condition of the component tolerances that narrows theclearance 200 most.

Accordingly, heat can be dissipated through the clearance 200 and,accordingly, a temperature rise inside the printer 100 can be reduced.

In the structure configuration illustrated in FIG. 1, both of the secondleft-side cover 112 and the third left-side cover 113, which leave theclearance 200, are fixed cover members fixed to the body frame 150,which is a body of the cabinet structure of the printer 100, with thescrews. As being fixed cover members, the two cover members, or thesecond left-side cover 112 and the third left-side cover 113, can bearranged without leaving a clearance at the boundary therebetween.However, provision of the clearance 200 allows heat to dissipate throughthe clearance 200, thereby reducing a temperature rise inside theprinter 100. Furthermore, arranging the cover members so as to leave theclearance 200 therebetween advantageously prevents galling, which is awear caused by sliding contact between the cover members adjacent toeach other, that would otherwise occur when attaching one of the covermembers in a state where the other one of the cover members is fixed.Hence, occurrence of a damage such as a scratch resulting from gallingcan be prevented.

Furthermore, in a structure configuration where the exterior-coverpieces are arranged with no clearance therebetween, even a slightdeviation from the component tolerances can cause the galling describedabove to occur or cause the exterior-cover pieces to interfere with eachother. By contrast, in the structure configuration where theexterior-cover pieces leave the clearance 200 therebetween, even ifthere is a slight deviation from the component tolerances, theexterior-cover pieces will not contact each other, and the galling orthe interference described above can be prevented. As a result,component tolerances are broadened, which leads to a reduction inmanufacturing cost.

It is desirable to arrange a more-frequently-attached/detached one ofthe exterior-cover pieces, or the second left-side cover 112 and thethird left-side cover 113, which leave the clearance 200 therebetween onthe outer side. In the structure configuration illustrated in FIG. 1,the third left-side cover 113 is arranged on the outer side at a portionwhere the clearance 200 is left. In the structure configurationillustrated in FIG. 1, only the third left-side cover 113 that is on theouter side at the portion where the clearance 200 is left can bedetached. If an attempt of detaching only the second left-side cover 112is made, the projecting-cover-section accommodating section 112 a thatis on the inner side of the projecting cover section 113 a of the thirdleft-side cover 113 is snagged on the projecting cover section 113 a,thereby making it difficult to detach only the second left-side cover112. Accordingly, the second left-side cover 112 is to be detachedtogether with the third left-side cover 113.

If the third left-side cover 113 that is detachable singly is theexterior-cover piece that is more frequently attached/detached than thesecond left-side cover 112, the detachment can be facilitated. Hence,this structure configuration allows, even with the labyrinth-shapedclearance at the boundary between the exterior-cover pieces adjacent toeach other, to maintain serviceability by reducing a drop in efficiencyin maintenance and replacement works.

Meanwhile, an occasion to detach an exterior-cover piece fixed to thecabinet of the printer 100 is substantially limited to replacement or alike operation performed by a maintenance person. Accordingly, arranginga more-likely-to-be-detached one of the two exterior-cover pieces on theouter side can prevent an undesirable situation that the otherexterior-cover piece is mistakenly opened (For example, themore-likely-to-be-detached exterior-cover piece may be an exterior-coverpiece facing a drive device; this is because a clutch included in thedrive device can possibly be replaced).

The length (L1 and L2 in FIG. 1) of portions, at which the secondleft-side cover 112 and the third left-side cover 113 overlap with eachother with the clearance 200 therebetween, in directions along which thepassage defined by the clearance 200 extends, is preferably 3.0millimeters or greater. Setting the length of the portions, at which theexterior-cover pieces that leave the clearance 200 therebetween overlapwith each other with the clearance 200 therebetween, to such a certainvalue prevents an undesirable situation that a portion of sound wavesthat is not diffracted in the clearance 200 leaks to the outside.

The second left-side cover 112 and the third left-side cover 113 thatleave the clearance 200 therebetween described with reference to FIGS. 1and 2 are the two exterior-cover pieces arranged to be laterally (in thehorizontal direction) adjacent to each other. However, embodiments ofthe present invention are not limited to such exterior-cover piecesarranged laterally adjacent to each other. For example, an embodimentmay be implemented in a structure configuration where the samelabyrinthine clearance as the clearance 200 is left at a boundary ofexterior-cover pieces that are vertically adjacent to each other as thefirst left-side cover 111 and the second left-side cover 112.

The structure configuration that creates the labyrinthine clearancedescribed above with reference to FIG. 1 is applicable to adjacent twoexterior-cover pieces configured as hinged cover members each of whichis operable to open and close about a pivot shaft.

FIGS. 5A and 5B are explanatory diagrams of a structure configurationwhere the third left-side cover 113, which is one of the exterior-coverpieces that leave the clearance 200 therebetween, is a hinged covermember operable to open and close. FIG. 5A is an explanatory diagram ofa state where the third left-side cover 113 is being closed. FIG. 5B isan explanatory diagram of a state immediately after the third left-sidecover 113 is closed with a force greater than necessary. The structureconfiguration illustrated in FIGS. 5A and 5B differs from thatillustrated in FIG. 1 in that the third left-side cover 113 is a hingedcover member operable to open and close.

In the structure configuration illustrated in FIGS. 5A and 5B, the thirdleft-side cover 113 is pivotable on a third-left-side-cover pivot shaft113 b. When the third left-side cover 113 in an open state is pressed bya user or a maintenance person in a direction indicated by arrow E inFIG. 5A, the third left-side cover 113 moves until it contacts the bodyframe 150. The third left-side cover 113 can thus be closed.

The position of a hinged cover such as the third left-side cover 113 ina closed state is determined by a positioning member such as the bodyframe 150. However, there can be a situation where the hinged cover iselastically deformed as is the third left-side cover 113 indicated bysolid lines in FIG. 5B. The clearance 200 is desirably sized so that,even in such a situation, a clearance indicated by α and β in FIG. 5B isleft between the two exterior-cover pieces which are the secondleft-side cover 112 and the third left-side cover 113, therebypreventing a contact between the exterior-cover pieces. Setting theclearance 200 in this manner prevents a damage resulting from contactbetween the exterior-cover pieces, thereby preventing reduction, whichwould otherwise be caused by the damage, in the sound-leakagesuppressing effect.

In the structure configuration illustrated in FIGS. 5A and 5B, thelabyrinthine clearance 200 is left between one end of the thirdleft-side cover 113, which is the hinged cover member, on the sideopposite from the third-left-side-cover pivot shaft 113 b and the secondleft-side cover 112. The reason therefor is described below. Becausemovable range of a hinged cover member is largest at one end on the sideopposite from its pivot shaft, it is required to make the clearance at aboundary between the hinged cover member and another cover member wideat the one end. This makes the one end vulnerable to sound leakage.However, sound leakage can be reduced even in such a structureconfiguration that leaves a wide clearance by imparting a labyrinthineshape to the clearance.

The clearance 200 is desirably sized as follows so as not to causecontact between the two exterior-cover pieces in the closed state. In astate where the third left-side cover 113 has been closed, the thirdleft-side cover 113 is positioned as indicated by dashed lines in FIG.5B. However, if the third left-side cover 113 is closed with a forcegreater than necessary, the third left-side cover 113 is brought intocontact with the body frame 150 and then elastically deformed whilemoving to the position indicated by the solid lines in FIG. 5B. Theclearance 200 is desirably sized to be greater than anexcessively-pushed distance W (FIG. 5B), which is the difference betweenthe lateral position of the distal end of the third left-side cover 113indicated by the dashed lines and that indicated by the solid lines.

It is desirable to set the excessively-pushed distance W using theposition of the distal end of the third left-side cover 113 in a statewhere the third left-side cover 113 is deformed maximumly within itslimit of elastic deformation as the position of the distal end of thethird left-side cover 113 indicated by the solid lines in FIG. 5B.Meanwhile, it is unnecessary to take into consideration a situationwhere the third left-side cover 113 is deformed beyond its limit ofelastic deformation. This is because when deformed beyond its limit, thethird left-side cover 113 is plastically deformed into a damaged stateand therefore cannot be used any more. By contrast, when the thirdleft-side cover 113 is deformed within its limit of elastic deformation,the third left-side cover 113 is not in a damaged state and continues tobe usable. Accordingly, by setting the excessively-pushed distance Wusing the position of the distal end of the third left-side cover 113deformed maximumly within its limit of elastic deformation, contactbetween the third left-side cover 113 and the second left-side cover 112can be prevented even though the third left-side cover 113 is deformedwithin an extent at which the third left-side cover 113 continues to beusable.

FIG. 6 is a perspective explanatory view of the printer 100,illustrating an example of a structure configuration where each of afront cover 120 which covers the near-side surface in FIG. 2 of theprinter 100 and a right-side cover 130 which covers the right-sidesurface of the same includes a hinged cover member.

The front cover 120 includes an upper front cover 121, which is a fixedcover member fixed to the body frame 150, and a hinged front cover 122,which is a hinged cover member pivotable on a front-cover pivot shaft122 a.

The right-side cover 130 includes an upper right-side cover 131 and alower right-side cover 132, which are fixed cover members fixed to thebody frame 150, and a hinged right-side cover 132, which is a hingedcover member pivotable on a right-cover pivot shaft 132 a.

The hinged front cover 122 can be opened by being pivoted on thefront-cover pivot shaft 122 a in a direction indicated by arrow F inFIG. 6. The right-side cover 130 can be opened by being pivoted on theright-cover pivot shaft 132 a in a direction indicated by arrow G inFIG. 6.

The pivot shaft of the third left-side cover 113 described above withreference to FIGS. 5A and 5B extends vertically. However, such astructure configuration as illustrated in FIGS. 5A and 5B that createsthe labyrinthine clearance 200 at a boundary between a hinged covermember and another cover member is also applicable to a structureconfiguration where the pivot shaft of the hinged cover member extendshorizontally as in the case of the hinged front cover 122 and the hingedright-side cover 132.

An image forming apparatus such as the printer 100 is typically requiredto include a hinged cover member, such as the hinged front cover 122 orthe hinged right-side cover 132, to be opened and closed when clearing apaper jam and when adding sheets of paper. However, if sound emittedinside the apparatus should leak to the outside through the clearancebetween such a hinged cover member and the other exterior-cover piece,the sound can be noise. If a structure configuration where the hingedcover member and the other exterior-cover piece are overlapped incontact with each other with no clearance therebetween should beemployed, even a slight deviation from component tolerances can causegalling or interference between the exterior-cover pieces to occur.

Accordingly, it is difficult not to leave a clearance with the structureconfiguration where the hinged cover member and the other exterior-coverpiece are overlapped in contact with each other. To eliminate theclearance, it is required to add an elastic member, such as a foamedplastic member, to a boundary portion between the hinged cover memberand the other exterior-cover piece. However, adding such an elasticmember to the exterior-cover pieces increases the number of componentsand can lead to an increase in manufacturing cost. Furthermore, becauseno clearance is provided, heat inside the apparatus cannot be dissipatedalong the boundary between the hinged cover member and the otherexterior-cover piece.

By contrast, the structure configuration that leaves the labyrinthineclearance 200 at the boundary between the hinged cover member and theother exterior-cover piece allows heat inside the printer 100 todissipate through the clearance 200, thereby reducing a temperature risewhile reducing leakage of sound from inside to the outside of theapparatus. Furthermore, because the need of adding an elastic member tothe boundary portion between the exterior-cover pieces is eliminated, anincrease in manufacturing cost can be reduced.

The printer 100 illustrated in FIG. 6 has a portion where the two hingedcovers, which are the hinged front cover 122 and the hinged right-sidecover 132, are adjacent to each other.

FIG. 7 is an enlarged horizontal cross-sectional top view of theboundary between the hinged front cover 122 and the hinged right-sidecover 132 of the printer 100. The arrow F and the arrow G in FIG. 7respectively indicate the direction in which the hinged front cover 122is opened and the direction in which the hinged right-side cover 132 isopened as described earlier with reference to FIG. 6.

The hinged right-side cover 132 includes a hinged-right-side-coverprojection 132 b projecting toward the inside of the apparatus at aposition slightly farther away from the hinged front cover 122 than anend of the hinged right-side cover 132 on the side of the hinged frontcover 122. The hinged front cover 122 includes a hinged-front-coverfirst projection 122 b, a hinged-front-cover second projection 122 c,and a hinged-front-cover third projection 122 d, which are arranged inthis order from an end of the hinged front cover 122 on the side of thehinged right-side cover 132 and each projecting toward the inside of theapparatus.

The clearance 200 between the hinged front cover 122 and the hingedright-side cover 132 assumes the labyrinthine shape with multiple bendsprovided by the above-described multiple projections (132 b, 122 b, 122c, and 122 d) and inner walls of the exterior-cover pieces. Accordingly,sound waves emitted inside the printer 100 and traveling toward theoutside through the clearance 200 are not allowed to go out of theprinter 100 unless the sound waves are diffracted multiple times as inthe structure configuration described earlier with reference to FIG. 1.

By employing the structure configuration that does not allow sound wavesemitted inside the printer 100 to leak out from the printer 100 unlessthe sound waves are diffracted multiple times in this manner, atemperature rise inside the printer 100 can be reduced while obtaining asound-shielding effect.

If both of the cover members that leave the clearance 200 therebetweenare hinged cover members as are the hinged front cover 122 and thehinged right-side cover 132, usability will be impaired unless thehinged cover members are operable to open and close irrespective ofwhich one of the hinged cover members is operated first. Meanwhile,sound leakage is more likely to occur at a portion where two hingedcover members are adjacent to each other. This is because the clearanceat this portion is made wider than those at portions where other covermembers are adjacent to each other by taking into consideration of themovable range. Even with such a disadvantageous condition as describedabove, sound leakage can be reduced by such a structure configurationwhich diffracts sound waves multiple times as illustrated in FIG. 7.

In the structure configuration including the hinged covers asillustrated in FIGS. 5A to 6, the clearance 200 is sized so as to permitfluctuations in tolerances of components including the second left-sidecover 112 and the third left-side cover 113 and fluctuations inclearances of movable units. More specifically, the dimensions of theclearance 200 are set to such values that will not cause the clearance200 to be closed by the second left-side cover 112 and the thirdleft-side cover 113 even in a condition of the component tolerances andthe clearances of movable units that narrows the clearance 200 most.

Accordingly, heat can be dissipated through the clearance 200 and, as aresult, a temperature rise inside the printer 100 can be reduced.

FIG. 8 is an enlarged horizontal cross-sectional view of the boundarybetween the second left-side cover 112 and the third left-side cover 113of the printer 100, in which the projecting cover section 113 a and theprojecting-cover-section accommodating section 112 a that leave theclearance 200 therebetween have tapered shapes 500 (a, b, c, and d).

The structure configuration illustrated in FIG. 8 differs from thatillustrated in FIG. 1 only in having the tapered shapes 500 (a, b, c,and d). Having the tapered shapes 500 (a, b, c, and d) makes contactbetween the exterior-cover pieces less likely to occur when mounting thesecond left-side cover 112 or the third left-side cover 113, therebyfacilitating mounting the exterior-cover pieces.

FIGS. 9A and 9B are explanatory diagrams of a structure configurationwhere a rib 113 c, which is a protrusion, is arranged on a portion ofthe projecting cover section 113 a of the third left-side cover 113 thatcreates the clearance 200. FIG. 9A is an enlarged horizontalcross-sectional view of the boundary between the second left-side cover112 and the third left-side cover 113. FIG. 9B is an explanatory diagramof the third left-side cover 113 as viewed from the right side of FIG.9A.

As illustrated in FIGS. 9A and 9B, the rib 113 c contacting the secondleft-side cover 112 is arranged on a surface of the third left-sidecover 113 at the portion where the exterior-cover pieces that leave theclearance 200 therebetween overlap with each other with the clearance200 therebetween.

The rib 113 c allows to maintain the distance between the thirdleft-side cover 113 and the second left-side cover 112 constant, therebypreventing deformation of the labyrinthine shape of the clearance 200.As a result, a disadvantageous situation that the clearance 200 iscrushed into a sealed state or that the clearance 200 is widened morethan necessary is prevented, and the size of the clearance 200 can bemaintained constant.

FIGS. 10A and 10B are top views of a structure configuration where theclearance 200 has three bends as in the embodiment described above,schematically illustrating the projecting cover section 113 a and theprojecting-cover-section accommodating section 112 a that are deformed.FIG. 10A is an explanatory diagram of pre-deformation. FIG. 10B is anexplanatory diagram of post-deformation.

FIGS. 11A and 11B are top views of a structure configuration where theclearance 200 has two bends, schematically illustrating a state wherethe projecting cover section 113 a and the projecting-cover-sectionaccommodating section 112 a that are deformed. FIG. 11A is anexplanatory diagram of pre-deformation. FIG. 11B is an explanatorydiagram of post-deformation.

In the structure configuration where the clearance 200 has two or lessbends as illustrated in FIGS. 11A and 11B, it is difficult to maintainthe shape which diffracts sound waves if the parts (113 a and 112 a)that leave the clearance 200 therebetween are undesirably deformed undersome force as illustrated in FIG. 11B. Therefore, if a portion of theparts that leave the clearance 200 therebetween is deformed, the effectof reducing sound leakage by diffracting sound waves may possibly not bemaintained any more.

By contrast, in the structure configuration where the clearance 200 hasthree or more bends as illustrated in FIGS. 10A and 10B, sound waves aretransmitted to the outside after undergoing diffraction three or moretimes. This structure configuration can advantageously maintain theshape that diffracts sound waves even if the parts (113 a and 112 a)that leave the clearance 200 therebetween are somewhat deformed.Accordingly, it is expected that the sound-leakage suppressing effectcan be maintained.

In the present embodiment, the example in which the cabinet structureincluding cover members is the cabinet of the image forming apparatushas been described. Embodiments of the present invention are alsoapplicable to any electronic equipment other than an image formingapparatus so long as the electronic equipment includes a sound sourcethat emits sound when in operation and a sound absorbing deviceconfigured to absorb the sound emitted from the sound source.

Applications of the structure configuration that creates the clearancewhich is a feature of the embodiments of the present invention are notlimited to electronic equipment. The structure configuration isapplicable to any cabinet structure for which reduction in sound leakagefrom inside to outside of the cabinet is desired.

FIG. 12 is a diagram illustrating cross sections of the cover members 1and 2, and a positioning member (structure body) 3. The right side ofthe figure is the inside of the electric equipment and the left side ofthe figure is the outside of the electric equipment. In the figure, eachof bent parts 1 a, 1 b, 1 c and 2 c of the cover members is continuouslyconnected, whereby following advantageous effects are expected inaddition to FIG. 1 of the present application.

-   -   A stress concentration is prevented and a durability of cover        members is improved.    -   It is less likely for an assembling worker and a user to get        injured because of smoothness of cover members.

Embodiments described above are merely examples, and the presentinvention provide advantage(s) specific to each of the followingaspects.

According to one aspect (aspect A), a cabinet structure, which may be anexterior cover of the printer 100, includes multiple cover members,which may be the second left-side cover 112 and the third left-sidecover 113, that spatially partition the inside from the outside of thecabinet. A clearance, which may be the clearance 200, communicatingbetween the inside and the outside of the cabinet is left between twocover members, which are adjacent to each other, of the multiple covermembers. A passage defined by the clearance and leading from the insideto the outside of the cabinet through the clearance has a shape withmultiple bends.

Accordingly, as described earlier in the embodiment, air is allowed tomove through the clearance that is left between the adjacent covermembers. As a result, heat accumulation inside the cabinet is prevented,and a temperature rise inside the cabinet can be suppressed.Furthermore, because the clearance has the complicated shape with themultiple bends, sound waves emitted inside the cabinet and travelingtoward the outside through the clearance are not allowed to go out ofthe cabinet unless the sound waves are diffracted multiple times.Because sound waves are weakened by being diffracted multiple times,even if the structure configuration having the clearance is employed,sound leakage through the clearance can be suppressed. Thus, the cabinetstructure including the multiple cover members according to aspect A canadvantageously reduce sound leakage while suppressing a temperature risein the cabinet.

According to aspect B, in the cabinet structure according to aspect A,the number of the bends is three or more.

Accordingly, as described earlier in the embodiment, because theclearance having the three or more bends increases the number of timesthat sound waves traveling toward the outside are diffracted as comparedwith a clearance having only two bends, the sound-leakage preventioneffect can be enhanced. Furthermore, having the three or more bendsallows maintaining the structure that diffracts sound waves even when aportion of the parts that leave the clearance, which may be theclearance 200, therebetween is deformed, thereby maintaining thesound-leakage suppressing effect.

According to aspect C, in the cabinet structure according to aspect A orB, both of the two cover members, which may be the second left-sidecover 112 and the third left-side cover 113, that leave the clearance,which may be the clearance 200, therebetween are fixed cover membersfixed to a body, which may be the body frame 150, of the cabinetstructure.

Accordingly, as described earlier in the embodiment, sound leakage canbe suppressed while suppressing a temperature rise inside the cabinet byvirtue of the complicatedly-shaped clearance deliberately left at theboundary between the fixed cover members.

According to aspect D, in the cabinet structure according to aspect A orB, at least one of the two cover members, which may be the secondleft-side cover 112 and the third left-side cover 113, that leave theclearance, which may be the clearance 200, therebetween is a hingedcover member operable to open and close.

Accordingly, as described earlier in the embodiment, even if theclearance is created at a portion operable to open and close, soundleakage can be reduced while reducing a temperature rise inside thecabinet by virtue of complicating the shape of the clearance.

According to aspect E, in the cabinet structure according to aspect D,both of the two cover members, which may be the second left-side cover112 and the third left-side cover 113, that leave the clearance, whichmay be the clearance 200, therebetween are hinged cover members operableto open and close. The two hinged members are operable to open and closeirrespective of which one of the hinged cover members is operated first.

Accordingly, as described earlier in the embodiment, the clearance canbe provided without impairing the sound-leakage suppressing effect.Furthermore, configuring the two hinged members to be operable to openand close irrespective of which one of the hinged cover members isoperated first prevents the structure configuration that creates thecomplicatedly-shaped clearance from adversely affecting usability.

According to aspect F, in the cabinet structure according to aspect D orE, the clearance, which may be the clearance 200, is sized to be greaterthan an excessively-pushed distance, which may be the excessively-pusheddistance W, which is a travel of the hinged cover member, which may bethe third left-side cover 113, from a position of the hinged covermember in a state where the hinged cover member has been closed to afarthest position to which the hinged cover member is movable whenforcibly pushed by a closing action.

Accordingly, as described earlier in the embodiment, even if the hingedcover member is pushed by a closing action farther inside than theclosed state where the hinged cover member has been closed, the hingedcover member is prevented from contacting the other cover member withwhich the clearance is created. Hence, a possible damage which wouldotherwise be caused by contact between the cover members that leave theclearance therebetween during an opening/closing operation can beavoided while maintaining the sound-leakage prevention effect providedby the complicated shape of the clearance.

According to aspect G, in the cabinet structure according to any one ofaspects D to F, the clearance, which may be the clearance 200, is sizedto permit fluctuations in component tolerances and clearances of movableunits.

Accordingly, as described earlier in the embodiment, even in a conditionof the component tolerances and the clearances of movable units thatnarrows the clearance most, heat can be dissipated through theclearance, so that sound leakage can be reduced while reducing atemperature rise inside the cabinet.

According to aspect H, in the cabinet structure according to any one ofaspects A to C, the clearance, which may be the clearance 200, is sizedto permit fluctuations in component tolerances.

Accordingly, as described earlier in the embodiment, even in a conditionof the component tolerances that narrows the clearance most, heat can bedissipated through the clearance, so that sound leakage can be reducedwhile reducing a temperature rise inside the cabinet.

According to aspect I, in the cabinet structure according to any one ofaspects A to H, the two cover members, which may be the second left-sidecover 112 and the third left-side cover 113, that leave the clearance,which may be the clearance 200, therebetween are arranged in such amanner that a more-frequently-attached/detached one of the cover membersis arranged on outer side.

Accordingly, as described earlier in the embodiment, even with thestructure configuration that creates the complicatedly-shaped clearanceat the boundary between the exterior-cover pieces adjacent to eachother, serviceability can be maintained by reducing drop in efficiencyin maintenance and replacement works.

According to aspect J, in the cabinet structure according to any one ofaspects A to I, the two cover members, which may be the second left-sidecover 112 and the third left-side cover 113, have tapered shapes, whichmay be the tapered shapes 500, at portions where the clearance iscreated.

Accordingly, as described earlier in the embodiment, assembling thecover members is facilitated.

According to aspect K, in the cabinet structure according to any one ofaspects A to J, a protrusion, which may be the rib 113 c, is arranged ona surface of at least one of the two cover members, which may be thesecond left-side cover 112 and the third left-side cover 113, that leavethe clearance, which may be the clearance 200, therebetween at a portionat which surfaces of the cover members overlap with each other with theclearance therebetween. The protrusion is arranged to contact thesurface of the other one of the cover members.

Accordingly, as described earlier in the embodiment, deformation of theclearance 200 is prevented, and a disadvantageous situation that theclearance is crushed into a sealed state or that the clearance iswidened more than necessary is prevented. As a result, the size of theclearance can be maintained constant.

According to aspect L, in the cabinet structure according to any one ofaspects A to K, length (L1 and L2, for example) of portions, at whichthe two cover members, which may be the second left-side cover 112 andthe third left-side cover 113, that leave the clearance, which may bethe clearance 200, therebetween overlap with each other with theclearance therebetween in directions along the passage is equal to orlarger than 3.0 millimeters.

Accordingly, as described earlier in the embodiment, an undesirablesituation that a portion of sound waves leaks to the outside withoutundergoing diffraction can be prevented because the portions at whichthe cover members that leave the clearance therebetween overlap witheach other with the clearance therebetween has the length of such acertain value.

According to aspect M, electronic equipment, which may be the printer100, including a sound source, which may be the drive devices and theoptical writing unit 27, that emits sound when in operation and acabinet, which may be the exterior-cover pieces, that covers the soundsource uses the cabinet structure according to any one of aspects A to Las the cabinet.

Accordingly, as described earlier in the embodiment, leakage of soundemitted to the outside when the electronic equipment is in operation canbe reduced while reducing a temperature rise in the cabinet when theelectronic equipment is in operation.

According to aspect N, an electro-photographic image forming apparatus,which may be the printer 100, includes a structure of the electronicequipment according to aspect M.

Accordingly, as described earlier in the embodiment, leakage of soundemitted in image forming process can be reduced while reducing atemperature rise inside the apparatus in the image forming process.

According to an aspect of the present invention, a cabinet structureincluding multiple cover members can advantageously reduce sound leakagewhile reducing a temperature rise in the cabinet.

Although the invention has been described with respect to specificembodiments for a complete and clear disclosure, the appended claims arenot to be thus limited but are to be construed as embodying allmodifications and alternative constructions that may occur to oneskilled in the art that fairly fall within the basic teaching herein setforth.

What is claimed is:
 1. A cabinet structure, comprising: multiple covermembers configured to spatially partition an inside from an outside of acabinet, the multiple cover members including a first cover member and asecond cover member adjacent to each other with a clearance therebetweenbetween the inside and the outside of the cabinet; a first protrusionprotruding into the inside of the cabinet from the first cover member;and a second protrusion protruding into the inside of the cabinet fromthe second cover member, wherein an end of the first protrusion issurrounded by at least the second protrusion on three sides thereof, andthe clearance is formed between the first protrusion and the secondprotrusion.
 2. The cabinet structure according to claim 1, wherein thefirst cover member and the second cover member are fixed cover membersfixed to a body of the cabinet structure.
 3. The cabinet structureaccording to claim 1, wherein at least one of the the first cover memberand the second cover member is a hinged cover member being operable toopen and close.
 4. An electronic equipment comprising: a deviceconfigured to perform an operation and emit sound during the operation;and the cabinet structure according to claim 1, the cabinet structureconfigured to cover the device.
 5. An image forming apparatuscomprising: the cabinet structure according to claim
 1. 6. A cabinetstructure comprising: multiple cover members configured to spatiallypartition an inside from an outside of a cabinet, the multiple covermembers including a first cover member and a second cover memberadjacent to each other with a clearance therebetween between the insideand the outside of the cabinet; a first protrusion protruding into theinside of the cabinet from the first cover member; and a secondprotrusion protruding into the inside of the cabinet from the secondcover member, wherein the clearance is formed so that an end of thefirst protrusion is surrounded by at least the second protrusion, and anend of the second protrusion and the end of the first protrusion overlapwith each other in a protrusion direction of the first protrusion. 7.The cabinet structure according to claim 6, wherein a length of aportion in a direction along the first protrusion is equal to or largerthan 3.0 millimeters, the portion being a portion at which the end ofthe first protrusion and the end of the second protrusion overlap witheach other.
 8. The cabinet structure according to claim 6, wherein thefirst cover member and the second cover member are fixed cover membersfixed to a body of the cabinet structure.
 9. The cabinet structureaccording to claim 6, wherein at least one of the first cover member andthe second cover member is a hinged cover member operable to open andclose.
 10. An electronic equipment comprising: a device configured toperform an operation and emit sound during the operation; and thecabinet structure according to claim 6, the cabinet structure configuredto cover the device.
 11. An image forming apparatus comprising: thecabinet structure according to claim 6.